Lancing aid comprising a lancet system that is protected against re-use

ABSTRACT

The present invention is generally directed towards the field of lancing aids in which disposable lancet systems are used. The lancet system according to the invention has a needle body which surrounds the needle tip in a lancet system in a protective manner and also comprises a protection against re-use of an ejected lancet system.

PRIORITY CLAIM

[0001] This application claims priority to German Application Number DE103 12 357.1 filed Mar. 20, 2003.

TECHNICAL FIELD

[0002] The invention concerns a lancet system that can be used in alancing aid for withdrawing blood for diagnostic purposes.

BACKGROUND AND SUMMARY

[0003] In a variety of diseases it is necessary to examine human bloodfor an analyte contained therein. In many cases this only requires thewithdrawal of a small amount of blood in the form of a blood drop byproducing a small puncture wound. A particularly important example ofsuch a case is diabetes in which the glucose content of blood has to beexamined at regular intervals. Blood may also for example be examinedwith regard to coagulation parameters, triglycerides, HbA1c or lactate.Blood lancet devices which consist of a lancing aid and a tailor-madereplaceable lancet are usually used to produce the required puncturewounds. The housing of the lancet instrument contains a lancet holder inwhich one interchangeable lancet can be inserted. During the lancingoperation the lancet holder is rapidly moved in a lancing direction by alancet drive of the lancet which is also integrated into the lancing aiduntil the needle tip emerges from an exit opening provided at the frontend of the lancing aid and produces a small puncture wound in the partof the body that is pressed against the front end. Afterwards the lancetholder containing the lancet is moved back in the opposite direction tolancing.

[0004] Small, easy-to-handle blood collection devices, so-called lancingaids that can be easily and reliably operated by the user and enable apart of the body to be lanced in an almost painless manner are nowroutinely used. In order to avoid infections especially in hospitals,the lancets are disposable elements intended for single use. After alancet has been used once, the lancet is removed after the lancingoperation or ejected from the device and discarded as refuse. In such acase the exposed needles in a refuse container may lead to injury duringwaste disposal resulting in a contamination of other persons by the usedlancet. Such contamination may lead to infections and thus somecountries are planning to impose a ban on blood collection systems inwhich the needle tip is freely accessible after use. In addition to arisk of injury during waste disposal there is also a risk that a usedlancet may be accidentally re-used. This is particularly relevant forhospitals in which a lancing aid is used for several patients since suchinadvertence of the nursing staff could lead to a patient beingcontaminated with the blood of a previous patient.

[0005] In addition to the use of blood lancet devices by medical staff,lancing aids are also used by laymen in the so-called home-monitoringfield. This is particularly the case for monitoring the treatment ofdiabetics. Thus it has been found in the treatment of diabetics thatserious damage associated with diabetes such as loss of sight can besubstantially reduced when the glucose concentration in the blood of thediabetic is determined frequently and up to five times daily and theinsulin injection is exactly adjusted on the basis of thesemeasurements. Lancing aids which enable the diabetic to carry out such ablood examination are used for home-monitoring in order to carry outsuch frequent measurements. The resulting requirements for a bloodlancet device are a simple handling when inserting new lancets and areliable ejection of used lancets in addition to a simple handling whentriggering the lancing operation and a relatively painless puncture.Lancet replacement should on the one hand be as simple as possible and,on the other hand, ensure the utmost safety with regard to unintentionalinjury of the user or other persons. Although in the home-monitoringfield it is conceivable that a lancet, once inserted, is used severaltimes for lancing by the same user, even in this case an accidentalre-use of an ejected lancet should be prevented once the user hasdecided to discard the lancet. Furthermore other persons in particularshould be reliably protected from the discarded lancets for exampleduring waste disposal.

[0006] In the prior art the tip of the needle is usually surrounded by atip cover made of plastic when the lancet is inserted which allows asafe insertion of the lancet. When the lancet is inserted, the tip coveris removed to expose the sharp tip of the needle for the lancingoperation (U.S. Pat. No. 5,628,765). However, due to the exposed needletip there is a risk of accidental injury and the tip may become damaged.The lancet is removed from the lancing aid after one or several lancingoperations. This can either be carried out manually in which case thereis a high risk of injury by the needle tip or by an automatic ejectionmechanism.

[0007] A blood lancet device is disclosed in the patent EP 0 565 970 inwhich the lancet is ejected from the lancet holder by means of anejecting rod. The user can operate the ejecting rod by pressing acorresponding button.

[0008] Furthermore an ejecting mechanism is described in the patentdocument U.S. Pat. No. 4,442,836 where the needle is automaticallyreleased when the lancing aid is retensioned so that the used lancet isdiscarded after each lancing operation. Such ejecting mechanisms requirea relatively high degree of additional engineering. Moreover multipleuse of an already inserted lancet system is not possible which is,however, often desired by customers especially in the home-monitoringfield. Another major disadvantage of the described prior art is that theneedle tip is unprotected after the lancet has been ejected resulting ina risk of injury as described above.

[0009] In order to facilitate the safe removal of a used lancet, bloodcollection systems are also described in the prior art which ensure theneedle tip is protected after ejecting the lancet. This is regarded asan important feature especially for elderly users or those that arehandicapped by poor sight and shaking hands as a result of disease.

[0010] A protection of the needle tip is achieved in the prior art byintegrating the lancet in a cap of the lancing aid such that the lancetand the housing cap together form a replaceable disposable unit. Suchdesigns are described in the documents EP 0595148 and U.S. Pat. No.4,990,154, U.S. Pat. No. 5,454,828 and DE 10053974. When the lancet isejected by the user, the housing cap is placed over the needle tip sothat the lancet surrounded by the cap can be subsequently discarded.Even if the needle tip is protected after ejection by the describedmechanism, it is nevertheless possible for a careless user to reinsert aneedle that has already been ejected once and carry out a new lancingoperation. Consequently the user is instructed to recognize that theneedle has already been used.

[0011] Only the document EP 0 630 609 discloses a mechanism whichdirectly prevents reinsertion and thus re-use of a lancet that has beenejected once. The described lancet device comprises a needle with aneedle body which breaks when the needle is ejected from the lancing aidto prevent a reinsertion of the needle. This prevents the user fromre-using a contaminated needle. However, a disadvantage of the prior artis that the needle tip is unprotected after the needle has been ejected.

[0012] The object of the invention is to provide an easy-to-use lancingaid preferably for the home-monitoring field which prevents re-use of analready ejected lancet system and also ensures a protection from injuryby the needle tip after the lancet system has been ejected. It shouldadvantageously be possible to easily re-use a needle of a lancet systemthat has been inserted once.

[0013] The object is achieved by a lancing aid and a lancet systemaccording to the independent claims. Preferred embodiments are derivedfrom the dependent claims.

[0014] The invention concerns a lancet system and a lancing aidcontaining the lancet system. The lancing aid has a housing forinserting a lancet system. The housing also has an opening where theneedle tip can emerge from the housing and a drive mechanism forcarrying out a lancing operation.

[0015] According to the invention the housing additionally has a holdingelement which can interact with a corresponding holding element of thelancet system as soon as the lancet system has been inserted in thelancing aid. The interaction between the holding elements enables thelancet system to be positioned in the housing at a defined site. Anexact positioning of the lancet system is important especially withregard to the drive mechanism for the lancing aid since it is the onlyway in which the needle can be correctly coupled to the drive mechanismsuch that the needle can perform a lancing operation at high speed andalmost without vibration. This enables a rapid and relatively painlesspuncture in the intended part of the body. In addition to the describedholding element, the lancet system for the lancing aid comprises atleast one needle with a tip which is suitable for producing an openingin the skin. The needle is connected to a needle body and at least oneprotective portion of the needle body and the needle can be removedrelative to one another. In a first position the needle tip is at leastpartially surrounded by the protective portion of the needle bodywhereas in a second position the protective portion of the needle bodyand the needle tip are disposed relative to one another such that theneedle tip is released from the protective portion of the needle body.If the protective portion of the needle body is in its first position,it thus guards against injury by the lancet tip which is particularlyimportant after the lancet system has been ejected from the lancing aid.

[0016] The needle body also contains a blocking mechanism which isactivated by an interaction with the lancing aid. The blocking mechanismchanges the needle body in such a manner that after the lancet systemhas been ejected from the lancing aid, the holding element on thelancing aid can no longer interact with the holding element of thelancing aid when it is reinserted. This prevents re-use of a lancetsystem that has been ejected once. In this connection the blockingmechanism can be automatically actuated as soon as certain operatingsteps have been carried out on the lancing aid. However, otherembodiments are conceivable in which the user actuates the blockingmechanism by a separate operating step.

[0017] As a result of the special design of the needle body, the lancetsystem according to the invention provides a protection from the needletip such that after ejection from the lancet system the tip issurrounded by the protective portion of the needle body to such anextent that injury by the tip is prevented. The blocking mechanism alsoinfluences the interaction of the holding elements. Within the scope ofthe invention the term interaction of the holding elements encompassesany conceivable embodiment that is known in the prior art for insertingand positioning a lancet or a magazine in a lancing aid. For example theholding elements can be snapped in or clamped. Suitable holding elementsfor this may for example be designed as locking lugs, grooves or hooksto name only a few possible embodiments. Similarly to the systemsdescribed in the prior art containing individual lancets, it is alsoconceivable that the lancet system is already adequately positioned andheld in the lancing aid due to its coupling to the drive unit so thatfor example the drive unit itself can be used as a holding element foran appropriately designed lancet system.

[0018] If several holding elements are provided to position the lancetsystem, the blocking mechanism advantageously prevents an interactionbetween the holding elements of the lancet system and the lancing aid sothat the lancet system cannot be held and positioned in the lancing aid.This is particularly advantageous when the lancet system and lancing aideach have several holding elements that act independently of oneanother.

[0019] In a preferred embodiment the interaction of the holding elementsis blocked in such a manner that the lancet system is prevented frombeing reinserted in the lancing aid. Within the scope of the inventionthe term “reinsertion” encompasses a handling of the lancet system suchthat the lancet system is positioned at the position in the lancing aidintended for carrying out the lancing operation and is held there due tothe interaction of the holding elements. For this purpose the lancetsystem is again used at its original position in the lancing aid thusrestoring the original state of the lancet system and lancing aid whichwas present when the lancing aid was first used.

[0020] When operating the lancing aid, the user can advantageouslyimmediately and unambiguously identify an already used lancet system forexample due to the fact that a reinsertion of the lancet magazine intothe lancing aid is blocked. Hence in contrast to the prior art the useris not required to consciously distinguish between a used lancet systemand a new lancet system. Advantageously the user is spared anunnecessary reinsertion of a used lancet system which no longerfunctions which elderly and visually handicapped persons often find tobe difficult.

[0021] However, it is also possible that the blocking mechanism onlyblocks the lancing operation in which case it is possible to reinsert aneedle that has already been ejected. If a reinsertion of the lancetsystem is prevented, this usually means that the lancet system cannotcouple to the drive unit.

[0022] In a preferred embodiment the blocking mechanism is essentiallyachieved by a change in the shape of the needle body. This proves to beparticularly advantageous when the shape of the needle body itself formsat least a part of a holding element. It is also possible that adeformation of the needle body spatially separates the holding elementsin the lancing aid such that the blocking mechanism has an indirecteffect on a holding element without directly acting on it. Hence thelancet system can no longer be positioned and held at a defined positionin the lancing aid. In a preferred embodiment the deformation of theneedle body transfers the protective portion of the needle body to afirst position such that there is no risk of injury when disposing aused lancet. The protective portion of the needle body and the blockingmechanism are then achieved as a single component of the lancet system.

[0023] In principle the holding elements can interact in a variety ofways. The blocking mechanism may have a direct or indirect effect on theholding elements. In the case of a direct effect on the holdingelements, at least one holding element is advantageously changed,covered or destroyed in such a manner that interaction of the holdingelements is no longer possible. Furthermore embodiments are alsoconceivable in which the lancet system is positioned within a lancingaid due to magnetic properties of the system. Hence a change in themagnetic properties of the needle body could prevent a re-use of thelancet system. Appropriate magnetic elements of the needle body orlancing aid are then the holding elements of the system.

[0024] Since the blocking mechanism advantageously only prevents arepeated insertion of the lancet system but does not prevent re-use of aneedle that has already been inserted, the lancet system also satisfiesrequirements in the home-monitoring field where multiple use of a onceinserted needle is often desired.

[0025] The lancing aid according to the invention for collecting bloodhas a drive unit with a plunger which moves a needle from its restingposition into a lancing position. A number of drive mechanisms are knownin the prior art that can be used in the field of blood collectiondevices (e.g. U.S. Pat. No. 5,314,442, WO 00/02482, U.S. Pat. No.3,030,959). In particular drive mechanisms are frequently used whichdraw their energy from a previously tensioned spring. Drive units arepreferably used within the scope of the present invention which enable aguided movement of the plunger and needle for example as a result of aform-fitting coupling as described in the document DE 10053974. Guidedmovements of the needle for example by means of guide blocks have alsobeen previously described in EP 0 565 970. Such drive mechanisms arepreferred because the puncture is less painful. However, the systemaccording to the invention is not limited to a particular drivemechanism, but on the contrary, can be combined with a variety of driveunits.

[0026] An important aspect of the invention is a lancet system that canbe detached from the drive unit containing at least one needle where thelancet system is provided as a disposable unit. In this connection theterm needle encompasses a blade-shaped substantially flat lancing unitand all other conceivable embodiments thereof. In principle needles canbe used for the invention that are basically well-known in the prior artand can be used in a lancet system. In the prior art a needle is oftencombined with a base body that can couple to the lancing aid which isreferred to as a lancet. Such lancets often have a base body made ofplastic in which a metal needle is disposed. According to the inventionit is possible to integrate such a lancet into the lancet systemaccording to the invention. It is for example conceivable that theneedle body according to the invention contains a base body like thatused for lancets in the prior art, where the inventive functionality ofthe system is maintained by integration of the base body. In this casethe needle body has an at least two-part design according to thedescribed embodiment. In a preferred embodiment the needle body isdesigned such that a plurality of lancets is disposed in the needle bodysuch that the needle body represents a magazine containing a pluralityof lancets and each base body of the lancet represents a part of theneedle body. Consequently in a preferred embodiment the protectiveportion of the needle body is formed by the magazine housing. The needleand the base body can then be guided in a movable manner within themagazine. The needles within a needle body designed according to theinvention as a magazine are preferably present in separate chambers inorder to prevent contamination of unused needles by used needles whenreloading.

[0027] In order to carry out a lancing operation, portions of the needlebody are advantageously designed like the system already described in DE10053974 such that the individual needles of the system can be activelycoupled to the drive unit of the lancing aid. Embodiments that can alsobe used to drive needles within a magazine of a lancing aid aredescribed for example in the documents DE 10053974, U.S. Pat. No.4,990,154 and U.S. Pat. No. 5,074,872. The chambers arranged next to oneanother in which the lancets are individually located are positionedsuccessively relative to the drive unit in order to carry out a lancingoperation in such a manner that in each case a single needle can becoupled to the plunger of the drive unit. Also in this case magazines inthe form of a drum containing chambers in which the needles are locatedparallel to the longitudinal axis of the drum have also proven to beparticularly advantageous.

[0028] The lancet system also advantageously comprises a needle bodywhich at least partially surrounds the needle tip by the protectiveportion of the body when the needle is in its resting position. In orderto carry out the lancing operation, the protective portion of the needlebody is spatially separated from the needle tip so that the protectiveportion of the needle body does not hinder the lancing operation. Whenthe lancet system is ejected from the lancing aid the needle remains inits resting position so that the ejected needle tip is protected andadditionally the blocking mechanism according to the invention preventsa re-use of the lancet system. It is, however, also possible that theprotective portion of the needle body is not transferred to its firstposition until the lancet system is ejected so that the needle tip isonly protected as a result of the ejection. In a preferred embodiment anunused needle is also in a resting position before insertion into thelancing aid to prevent injury by the needle tip and contamination whenthe needle is inserted as well as after ejection.

[0029] A blocking mechanism according to the invention can be actuatedfor example when the lancet system is ejected from or inserted into thelancing aid independently of the needle tip protection. In principle theblocking mechanism or the needle tip guards can also be activatedseparately or by means of individual operating steps of the lancing aide.g. during the lancing operation. In general all possible combinationsare conceivable which ensure a simultaneous or successive blockingmechanism and protection of the needle tip.

[0030] The blocking mechanism can have a variety of designs but it isadvantageous that the shape of the needle body is changed in such amanner that it is no longer possible to reinsert a lancet system once ithas been ejected. For example the blocking mechanism can move at leastone part of the needle body that interacts with the lancing aid in sucha manner that a change in its position blocks a reinsertion of thelancet system. This is for example the case when the blocking mechanismcloses a recess in the needle body which forms a holding element or arecess is generated in the needle body that is essential for aninteraction of the lancet system with a lancing aid. Furthermore it isalso possible that the blocking mechanism comprises a predeterminedbreaking point which results in a breaking of the needle body when thelancet system is ejected. It is also conceivable that the needle body isenlarged, made smaller or bent which are only a few methods fordeforming the needle body.

[0031] According to the invention an interaction between the lancetsystem and lancing aid activates the blocking mechanism and sets a firstposition of the protective portion where the protective portion at leastpartially surrounds the needle tip.

[0032] An important requirement for the lancet system is that the needletip that is used to produce a wound in an appropriate part of the bodyis sterile. The sterility of the needle tip has to be ensured over along period which extends from the manufacture of the lancet system upto its use. Sterility can be achieved during the manufacture of thelancet system by for example gamma radiation which is commonly used inthe prior art. In order to maintain sterility, the lancet system can besealed in a wrapping, for example a polyethylene bag. In anotherembodiment the opening of the lancet system where the needle tip emergesfrom the protective portion of the needle body can for example be closedby a sealing foil. These are preferably detachable sealing foils whichthe user removes before using the lancet system. However, it is alsopossible to use thin foils which are not pierced by the needle tip untilthe needle is used so that the user does not have to carry outadditional handling steps. Such foils may already be used as an integralpart of the manufacturing process for the lancet system which is usuallyby means of an injection moulding process.

[0033] Furthermore in the prior art an elastomer is described in theapplication WO 01/66010 for sterile protection which encloses the needletip and thus protects it against contamination. This sterile protectioncan either be pierced during the lancing operation or be removed by theoperator before use.

[0034] In another advantageous embodiment the protective portion of theneedle body can comprise a sterile protection and/or the protectiveportion can be essentially formed thereby. In this case the elastomer ofthe sterile protection serves for example as the protective portion ofthe needle body by the fact that the needle tip can be moved in a guidedmanner relative to the elastomer. Another part of the needle body thatcan be actuated independently of the sterile protection is able tochange the needle body and represents the blocking mechanism. Thisrequires that the sterile protection can reversibly expose the needletip and surround it again which is for example the case with anelastomer protection (WO 01/66010) in which the elastomer is firstlypierced during the lancing operation and subsequently the needle tip isretracted into the elastomer. Consequently in this example the needletip changes its position relative to the sterile protection during thelancing operation and the needle tip is protected by the sterileprotection in its resting position after the lancing operation. Inprinciple many embodiments of a sterile protection are conceivable andhence the inventive system is not limited to any special embodiment of asterile protection.

[0035] Further features and advantages of the invention will becomeapparent from the following discussion and the accompanying drawings inwhich: The system according to the invention is illustrated in thefollowing on the basis of the figures and examples without being therebylimited to the individual examples.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036]FIG. 1(a) to FIG. 1 (d) is a perspective view of a two-part lancetsystem;

[0037]FIG. 2 (a) to FIG. 2 (d) is a perspective view of the Lancetsystem in which the blocking mechanism is activated during the lancingoperation;

[0038]FIG. 3 (a) to FIG. 3 (f) is a perspective view of the blockingmechanism that is activated when the system is ejected;

[0039]FIG. 4 (a) to FIG. 4 (d) is a perspective view of the Lancetsystem with a blocking mechanism which prevents a lancing aid fromcoupling to the lancet system;

[0040]FIG. 5 (a) to FIG. 5 (c) is a perspective view of the Lancetsystem with a blocking mechanism which is activated when it is insertedin the lancing aid;

[0041]FIG. 6 (a) to Figure (h) is a perspective view of the Lancing aidwith a lancet magazine; and

[0042]FIG. 7 (a) to FIG. 7 (e) is a perspective view of the Lancetsystem with a blocking mechanism which widens the needle body.

DETAILED DESCRIPTION

[0043] The following description of the preferred embodiment is merelyexemplary in nature and is in no way intended to limit the invention orits application or uses.

[0044]FIG. 1 shows a lancet system (1) which is essentially in twoparts. FIGS. 1b and 1 d each show a cross-section through the lancetsystem shown in FIGS. 1a and 1 c before and after use respectively. Thesystem has a needle (3), the front tip of which is wrapped in a sterilemanner with an elastomeric protection (4). Such elastomers which ensurethe sterility of the needle tip are known for example from the documentWO 01/66010 to which reference is herewith made. The metallic needle (3)is attached to a plastic body (2 b) and is permanently connectedthereto. The plastic body has a rear portion (6) which couples thelancet system to a drive plunger such that the needle can be moved alongthe axis (8) in the direction of lancing. The rear portion (6) of theplastic body which is a part of the needle body comprises two arms whichcan connect in a form fitting manner during the lancing operation with adrive plunger of a lancing aid (not shown) by means of the projectingparts (11). A form-fitting connection between a drive plunger and lancetis described for example in the document DE 10053974 to which referenceis also herewith made. Of course any other coupling mechanism that isdescribed in the prior art is conceivable for carrying out the lancingoperation. The needle (3) and the plastic body (2 b) that is permanentlyconnected thereto are movably mounted in the plastic body (2 a) whichrepresents the protective portion of the needle body. The needle and thesecond part of the needle body (2 b) can be moved within this needlebody along the direction of lancing. The protective portion of theneedle body (2 a) has a lower wall (10) which has a hole (9) throughwhich the needle tip can emerge during the lancing operation. The needlebody also has an opening (7) at its upper end through which a driveplunger of a lancing aid can be inserted into the needle body in orderto connect in a form-fitting manner with the second part of the needlebody and perform the lancing operation. The protective portion of theneedle body (2 a) also has two recesses (13 and 14) which allow it to belocked into the second part of the needle body (2 b). In order to enablethe second part of the needle body to engage in the protective portion,the rear portion (6) of the second part of the needle body also haslocking lugs (12) which engage in the recesses (14) in a first restingposition of the lancet system before use and hold the second part of theneedle body due to the spread arms (6). The middle portion of theprotective portion and of the second part of the needle body havetrough-shaped taper (5 and 5′) of the body such that the tapered parts(5 and 5′) exactly fit together in the first resting state before thelancet system is used and the lancet system in this position has thedesign shown in FIG. 1a.

[0045] In order to carry out the lancing operation, a plunger (notshown) of the lancing aid engages through the opening (7) into thelancet system where the plunger connects in a form-fitting manner withthe arms (6) of the second part of the needle body. As a result the arms(6) are pressed together so that the lugs (12) of the arms (6) no longerengage in the recesses (14) and the needle can be moved forwards alongthe lancing direction (8). In this process the elastomeric protection(4) is firstly pressed against the lower wall (10) of the needle body (2a). If the lancing operation is continued the needle is driven throughthe elastomeric protection and can thus emerge from the opening (9) inthe lower wall (10) and produce a wound in the intended part of thebody. The elastomeric protection (4) is meanwhile held back by the wall(10) as a result of which the front part (15) of the second part of theneedle body (2 b) corresponding to the recess (16) can move over theelastomeric protection. After the lancing operation has been carriedout, the needle body (2 b) and the needle are subsequently retractedinto the protective portion (2 a) due to the form-fitting coupling tothe drive plunger. Once the rear arms (6) are in the rear protectiveportion of the needle body (2 a), the lugs (12) can engage in the recess(13) of the needle body (2 a) when the needle body (2 b) is pulled back.The lancet system is now in a second resting position after the lancingoperation. In this position the second part of the needle body (2 b)protrudes from the opening (5) of the protective portion of the needlebody (2 a) in such a manner that the needle body is deformed in thisarea. The tapered parts (5 and 5′) no longer fit together. In a lancingaid designed in a corresponding manner which only allows insertion of alancet system when the tapered part (5) of the needle body is completelyformed according to FIG. 1a, insertion of an already used lancet systemis blocked according to FIG. 1c.

[0046] The example shown in FIG. 1 has a blocking mechanism and enablesthe protective portion of the needle body to be transferred to a firstposition during the lancing operation. When the lancet system is ejectedafter the needles have been used, the shape of the system has alreadybeen changed in such a manner that it is no longer possible to reinsertthe lancet system in an appropriately designed lancing aid. Furthermorethe needle tip is completely surrounded by the protective portion andhence there is no risk of injury for other persons e.g. during wastedisposal.

[0047]FIG. 2 shows a lancet system in the form of an essentially roundlancet magazine. In comparison with FIG. 1 the protective portion of theneedle body (2 a) is only designed as a magazine so that a plurality ofneedles (3) can be movably guided therein.

[0048]FIG. 2a shows an outer view of a magazine. The magazine housingwhich forms the protective portion of the needle body is designedsimilarly to FIG. 1 and has recesses (13 and 14) into each of which thelocking lugs (12) of the respective second part of the needle body (2 b)can engage. The lancet system has a magazine axis (21) that is arrangedconcentrically in the protective portion of the needle body and is usedas a bearing for the lancet system in a lancing aid. The lancet systemcan be rotated around the axis (21) so that one needle in each case canbe positioned relative to a drive unit (not shown) in the lancing aid.Like the lancet system shown in FIG. 1, the lancet system in FIG. 2 alsohas tapered parts (5) within the protective portion of the needle body(2 a) which are in the form of openings where the openings are alsoessentially tightly closed by the second part of the needle body (2 b).

[0049]FIG. 2b shows a cross-section through the lancet magazine shown inFIG. 2a. The system has a similar structure to that of FIG. 1, butconsists of a plurality of needles that are equipped with an associatedsecond part of the needle body (2 b). Consequently the lancet systemshown in FIG. 2 has several parts which include an outer protectiveportion of the needle body and several second parts (2 b) of the needlebody. FIGS. 2c and 2 d show the lancet system after use in which allneedles of the lancet system have already been used for lancing. It isof course also possible that only some of the needles have already beenused in the lancet system. In this case the second part (2 b) of theneedle body would only protrude through some of the openings (5) of theprotective portion of the needle body (2 a) whereas the other openingswould be tightly closed by the needle body as shown in FIG. 2a.Depending on how the lancet system interacts with the lancing aid,embodiments are conceivable where reinsertion of the lancet system intoa lancing aid is already blocked as soon as some of the needles havebeen used or is only blocked after all needles have been completely usedin the lancet system. Advantageously it is also conceivable that thereinsertion of a partially used lancet system into the lancing aid isonly possible when the system has been positioned relative to the driveplunger in such a manner that only unused lancets can be used by thesystem.

[0050]FIG. 3 shows a rectangular needle body which also comprises aplurality of needles in the form of a magazine. The protective portionof the needle body (2 a) also has openings (9) in its lower end (10)from which the needles can emerge to perform a lancing operation. Whilein their resting position i.e. when no lancing operation is carried out,the needle tips of the needles (not shown) are within the protectiveportion of the needle body (2 a) in which the needles can be movablyguided. The needle body (2 a) contains grooves in a lower portion (34)that borders the lower end (10) of the needle body which make it easierto grip and thus facilitate its handling by the user. Recesses (33) areprovided in this portion (34) as holding elements which, in anappropriately designed lancing aid, enable the lancet system to lockinto the lancing aid during insertion. The blocking mechanism (31) islocated in the middle of the needle body (2 a) as part of the needlebody (2 a) and can be movably guided to an upper portion (35) of theneedle body (2 a), and is firstly held in a starting position byspring-mounted arms (39). There is also a recess (32) in the upper part(35) which locks the blocking mechanism (31) when the blocking mechanism(31) is guided along the upper part of the needle body (35).

[0051]FIG. 3b shows the lancet system after use. As illustrated in FIG.3b, the blocking mechanism (31) that surrounds the needle body (2 a) inthe form of a ring is now positioned at the upper end of the needle bodyso that the blocking mechanism (31) in this position widens the needlebody section (35). Once the blocking mechanism (31) has been locked intoits position, it is no longer subsequently possible to reinsert thelancet system due to the enlarged needle body.

[0052]FIGS. 3c and 3 d illustrate in more detail the operation of theblocking mechanism (31) which is used in the lancet system describedabove. In order to lock the blocking mechanism (31) in the upper portion(35), the blocking mechanism has locking arms (36) which engage in therecesses (32). In the position shown in FIGS. 3b and c the locking arms(36) are spring-mounted against the lower edge of the recess (32) tosecure the blocking mechanism (31) against displacement. The stop (37)also serves as an additional counter-flange of the blocking mechanism(31) against the projection (38) in the upper portion of the needle bodycomponent (35). When the magazine is inserted as shown in FIG. 3e forfirst use in a lancing aid housing (70), the rear portion (35) of themagazine housing is positioned in an appropriately tapered position (82)of the housing (70). In contrast the front portion (80) of the housing(70) is widened so that the widened diameter of the lancet system due tothe ring that acts as the blocking mechanism can be placed accordinglyin the lancing aid housing. In this position the lancet system is heldin the lancing aid in such a manner that a drive unit (not shown) of thelancing aid can engage in the magazine housing in order to couple onto aneedle of the lancet system. The lancing aid housing also has two stops(83, 84) which are adjacent to the blocking mechanism (31) in thisposition of the lancet system in the lancing aid. If the lancet systemis removed from the lancing aid housing after use, the stop (84) firstlyhas the effect that the blocking mechanism (31) remains fixed inposition in the lancing aid housing while the magazine housing is pulledout of area (82) of the lancing aid. As a result the blocking mechanism(31) is pushed along the needle body to the upper portion (35) of theneedle body. In this process the blocking mechanism (31) locks with theneedle body and the projection (38) and the stop (37) block furthermovement of the blocking mechanism along the needle body. If theblocking mechanism (31) rests against the projection (38), a furtherpulling movement on the magazine housing overcomes the resistance of thestop (84) and the magazine can be removed from the lancing aid. Themagazine is now outside the housing in a used state as shown in FIG. 3bwhere the blocking mechanism (31) is permanently positioned on theneedle body due to the locking hooks (36) and the stop (37). If thelancet magazine is reinserted into the lancing aid housing, the magazinecan no longer be pushed into the tapered area (82) of the lancing aiddue to the widened circumference of the upper section (35) of the needlebody. Hence it is no longer possible to position the lancet system inits original position in the lancing aid. The lancet system can nolonger be held in the lancing aid. The coupling of individual needles tothe drive unit of the lancing aid in order to carry out a lancingoperation is blocked. Moreover after the lancet system has been ejected,the user can easily visually recognize that the lancet system is a usedsystem due to the displaced ring. For this purpose it is alsoconceivable that the blocking mechanism (31) is highlighted in colour.

[0053] As an alternative to the described change in the needle body (2a), it is for example also conceivable that the blocking mechanism (31)can be moved over the recesses (33) of the lancet system. In this case areinsertion of the lancet system in a lancing aid would be preventedbecause the lancet system could no longer lock into the lancing aid.Other embodiments using a movably mounted blocking mechanism areconceivable which for example result in a reduction in the size of theupper section (35) of the needle body. In this case an unused lancetsystem e.g. in the state shown in FIG. 3b, is firstly placed in alancing aid. A used lancet system would then be characterized in thatthe blocking mechanism (31) would have been pushed over the needle bodyportion (35) in such a manner that the upper section (35) of the needlebody (2 a) is diminished in size. FIG. 3a would thus represent theejected state of the system. A correspondingly designed lancing aidwould then for example have holding elements that could no longerinteract with a lancet system that has been changed in this manner andreinsertion into the lancet system would no longer be possible. Thelocking elements of the blocking mechanism and of the needle body (2 a)would then have to be adapted accordingly. Furthermore it is alsoconceivable that a movable blocking mechanism (31) ensures that areinsertion of the lancet system is blocked and also protects the needletips. In this case the needle tips would not, as shown in FIG. 3, beretracted into a protective portion of the needle body after the lancingoperation. Hence the needle tips would not be automatically protected ina resting position. For example protection from the needle tips wouldnot be ensured until the lancet system has been ejected from the lancingaid. According to the blocking mechanism shown in FIG. 3a, a movement ofthe blocking mechanism (31) elongates the needle body in the area of theneedle tips so that the needle tips are surrounded in a protectivemanner by the blocking mechanism and at the same time the blockingmechanism is activated due to a change in the shape of the body. In thiscase a part of the needle body acts as a blocking mechanism and also asa protective portion of the needle body which surrounds the needle tiparea when the lancet system is ejected. The protective portion of theneedle body and the blocking mechanism then comprise one structuralelement of the needle body.

[0054]FIG. 4 shows a rectangular lancet system in which several needlesare positioned in chambers (42) of the protective portion of the needlebody (2 a). The upper section of the protective portion of the needlebody has a blocking mechanism (41) in the form of a button which islocated above the protective portion of the needle body and can be movedalong direction (45) towards the protective portion of the needle body.The upper part of the button has a guide groove (49) which engages in amatching lip of the lancing aid (not shown) so that the lancet systemcan be securely positioned in the lancing aid. Once positioned in thismanner, a drive plunger of the lancing aid (not shown) can couple withthe rear area (48) of the needle (3) to carry out a lancing operation.For this purpose the needle is moved along direction (43) relative tothe protective portion of the needle body and the needle tip emergesfrom the protective portion (2 a) of the needle body. As in the systemsthat have already been described, the needles are returned to themagazine after the lancing operation and the needle tip is retractedwithin the needle body (2 a). The magazine is moved to the next positionby moving the drive plunger of the lancing unit along direction (44)until the plunger can couple with a needle positioned in the adjacentchamber (42) in order to carry out a new lancing operation. If thelancet system has to be replaced in the lancing aid, the drive plungermust firstly be moved outside the rear area (46) of the needle body (2a). For this purpose the magazine is moved to the next position and atthe same time the button (41) is pressed down by a ramp on the housingof the lancing aid. The button (41) is now shifted within the lancetsystem as shown in FIGS. 4c and d so that the section (50) of the buttonprotrudes from the bottom of the needle body (2 a). In this position arecess (47) of the button (41) engages the rear area (48) of the needle(3) which prevents the lancing aid from coupling again with the lancetsystem as shown in the front view of FIG. 4d. Hence a lancing operationcannot be carried out with a lancet system of FIG. 4c or d. Moreover thelancet system cannot be reinserted into the lancing aid due to thechange in the shape of the needle body in area (50). Hence the lancetsystem cannot be positioned via the guide groove (49) as part of aholding element.

[0055]FIG. 5 shows a round-shaped lancet system which also containsseveral needles within the needle body. Similarly to FIG. 2, the lancetsystem has a multipart needle body. A channel (52) is arranged along theaxis of rotation of the lancet system and a plug (53) is located in thischannel at the upper end of the lancet system. The plug (53) is held inits first position by expanding holding arms (56) and this positionrepresents the unused state of the lancet system. The holding arms (56)engage in a taper of the plug (53) which is formed by planes (55) of theplug which slant towards one another. When the lancet system is insertedinto a lancing aid (70) the plug (53) is pressed within the channel (52)towards the needle tips by means of a centering plunger (57) of thelancing aid. The holding arms (56) are spread when the plunger ispressed in due to the slanting planes (55) of the plug (53). When theholding arms (56) of the lancet system are spread the plunger (57) canengage between them. Hence the plunger (57) can be almost completelyinserted into the lancet system and is used as a bearing for and toposition the magazine. An appropriately designed drive unit of thelancing aid can thus be oriented relative to the lancets of the systemsuch that it can be coupled to a lancet and a lancing operation can becarried out. After the magazine has been used it is removed from thelancing aid. For this purpose the plunger (57) is pulled out from theinterior of the magazine housing while the plug (53) remains at thelower end of the magazine in the area of the needle tips. Consequently aused lancet system is designed as shown in FIG. 5c in which the plug(53) is no longer held in the upper section of the holding arms (56). Ifan attempt is made to insert the used lancet system into the lancingaid, the plunger (57) strikes the upper portion (56) of the holding armswhich in their unspread state prevent the plunger from penetrating intothe lancet system. The absence of the plug (53) prevents the plunger(57) of the lancing aid from spreading the holding arms and thus thelancet system cannot be placed in the lancing aid.

[0056]FIG. 6 shows another embodiment of a lancet system that isarranged within a lancing aid. FIG. 6a to d firstly show a lancet systemthat is similar to that of FIG. 1. Like FIG. 1 the system shown in FIG.6 also has an elastomer (4) which surrounds the needle tip in a sterilemanner and a two-part needle body which has a taper (5, 5′) in itsmiddle. The second part of the needle body (2 b) whose movement isguided in the interior of the protective portion of the needle body (2a) also has arms (6) in its rear section which can couple in aform-fitting manner with a plunger (78) of the lancing aid (72). Asshown in FIGS. 6b and c, the plunger (78) engages with a head (71) inthe second part (2 b) of the needle body and moves the needle along theaxis (8) in the direction of lancing. In this process the arms (6) ofthe needle body (2 b) are pressed together and the projections (11)engage behind the notches in the head (71). The mode of operation of thelancet system is similar to that already described in FIG. 1 and is thusonly shown again here with regard to its interaction with the lancingaid. The lancing aid (72) has a locking lever (74) that is mounted inthe lancing aid and is rotatably pivoted on an axis (75). The lockinglever (74) has a circular shape in a first area (77) such that thelocking lever can engage in a form-fitting manner in the taper (5) ofthe lancet system.

[0057]FIG. 6a shows the state of the lancing aid with the lancet systembefore use in the inserted state. If it is intended to use the lancingaid for a lancing operation, the locking lever (74) is rotated by about90° either automatically when a lancing operation is triggered orseparately by the user, such that the lower section (77) of the lockinglever no longer engages in the taper (5, 5′). The rotation of thelocking lever is ensured by the fact that the lancing aid also has adepression (76) in the housing of the lancing aid which allows thelocking lever to rotate around the axis of rotation (75). When thelancing operation is carried out, the second part of the needle body (2b) can move along the protective portion of the needle body (2 a) and asection of the needle body (2 b) emerges from the opening of the needlebody (2 a) without being hindered by the locking lever (74). In thisprocess the needle tip is driven through the elastomer and the exitopening (9) of the lancet system and through an exit opening (73) of thelancing aid.

[0058] After the lancing operation the needle returns to its restingposition during which, however, the second part of the needle body locksinto the recess (13) of the protective portion of the needle body. Asalready described in FIG. 1, this results in a change in the outer shapeof the needle body in the area of the taper (5) since the second part ofthe needle body (2 b) now protrudes from the opening of the needle body(2 a). After the lancet system has been removed from the lancing aid,the locking lever (74) rotates back into its initial position as shownin FIG. 6a. As indicated in FIG. 6d, a reinsertion of the lancet systeminto the lancing aid is blocked by the locking lever (74). The lockinglever (74) can no longer engage in the taper (5) of the used lancetsystem since the taper (5) is partially closed by the second part of theneedle body (2 b). Hence the lancet system can no longer be positionedand thus held in its original position. The plunger (78) can no longerengage in the lancet system. The head (71) and the projections (11) areprevented from forming a form-fitting connection.

[0059]FIGS. 6e-h show embodiments similar to FIGS. 6a-d in which thelancet system consists of a plurality of needles so that they can bestored in a magazine as shown in FIG. 2. The operating principles are,as already described, identical and can be simply transferred from thesystem with one needle to the system shown in FIGS. 6e-h. At this pointthe intention is only to illustrate an embodiment that allows a magazineto be reinserted whose needles have only been partially used. For thisthe user must rotate the magazine relative to the lancing aid housinguntil the locking lever (74) can engage in a taper (5) which is notblocked by a needle body (2 b). This positioning of the lancet systemrelative to the lancing aid and consequently relative to the driveplunger ensures that only a lancet that has not yet been used isemployed for the next lancing operation. An advance of the lancet systemin only one direction of rotation and a mechanism that allows no morethan one rotation of the lancet system by 360° can be added as requiredin order to prevent already used lancing aids from being used again.

[0060]FIG. 7 shows another embodiment of a lancet system that is in theform of a round magazine housing. The needle body design has severalparts similar to the figures that have already been described. Thesterile protection and needles are also arranged as already describedand thus a more detailed description is omitted here. Similar to thesystem described in FIG. 5 the blocking mechanism shown in FIG. 7 isalso actuated when the lancet system is inserted into the lancing aid.For this purpose the needle body (2 a) has a blocking mechanism (31)that is in the form of an outer ring that surrounds the upper section(35) of the needle body. When positioned at this position the blockingmechanism (31) essentially covers the elastic arms (90) that are locatedin the upper portion of the needle body (35). As a result the elasticarms (90) are pressed into the recess (95) of the needle body (2 a). Theblocking mechanism (31) also has a circular protrusion at its lower endthat enlarges the circumference of the needle body (2 a) at thisposition. If the lancet system is inserted into a lancing aid, thecircumference of the lancing aid is selected such that the ring (96)cannot be inserted into the lancet system. The ring is pressed downwardsrelative to the needle body into the area of the lancet tips when thelancet system is inserted into the lancing aid by means of a lower edge(97) acting as a counter-flange for the lancing aid housing. As a resultthe spring-mounted locking arms (90) are released from the ring. Theresting arms are now in a spread state in the lancing aid and arepressed against the inner housing wall (98) of the lancing aid. When aused lancet system is removed from the lancing aid, the locking arms(90) slide along the sloping housing wall (98) in a tapered area of thelancing aid housing and are firstly pressed into the recess (95) of theneedle body due to the slanting wall (98). Hence the lancet system canbe readily removed from the tapered area of the lancing aid. The usedlancet system is subsequently present in a changed form as shown in FIG.7c. When the system is reinserted into a lancing aid the locking arms(90) are now spread and thus the circumference of the needle body (2 a)is enlarged in the area (35) thus preventing an insertion of the lancetsystem into the front narrowed area of the lancing aid.

[0061] As any person skilled in the art will recognize from the previousdescription and from the figures and claims, modifications and changescan be made to the preferred embodiment of the invention withoutdeparting from the scope of the invention as defined in the followingclaims.

What is claimed is:
 1. A lancing aid for producing an opening in theskin, the lancing aid comprising: a housing for inserting a lancetsystem, wherein the housing has a holding element that interacts with aholding element in the lancet system when the lancet system ispositioned in the housing; at least one needle having a needle tip,wherein the at least one needle is connected to a needle body, whereinthe needle body comprises a protective portion such that the protectiveportion of the needle body and the needle can be moved relative to oneanother; wherein the protective portion of the needle body partiallysurrounds the needle tip in a first position; wherein the protectiveportion of the needle body and the needle tip are arranged relative toone another in a second position in such a manner that the needle tip isreleased from the protective portion of the needle body; an opening inthe housing, wherein the needle tip of the at least one needle canemerge from the lancet system during a lancing operation; a drivemechanism for propelling the at least one needle such that the needle istransferred from a resting position into a lancing position; and ablocking mechanism comprised in the needle body, wherein the blockingmechanism is actuated by an interaction with the housing such that afterejection of the lancet system from the housing, the holding element ofthe housing is prevented from interacting with the holding element ofthe lancet system when the lancing system is reinserted into thehousing.
 2. The lancing aid as claimed in claim 1, wherein the holdingelement of the housing is prevented from interacting with the holdingelement of the lancet system in such a manner that the lancet systemcannot be reinserted into the housing.
 3. The lancing aid as claimed inclaim 1, wherein the lancet system and the housing each have several,and independently acting holding elements.
 4. The lancing aid as claimedin claim 1, wherein the blocking mechanism prevents an interaction ofthe holding elements of the lancet system with the housing such that thelancet system can be held and positioned in no position in the housing.5. The lancing aid as claimed in claim 1, wherein an interaction of theholding elements of the housing and the lancet system is prevented insuch a manner that the needle cannot be propelled by the drivemechanism.
 6. The lancing aid as claimed in claim 1, wherein theblocking mechanism spatially separates the holding elements when thelancet system is reinserted into the housing.
 7. The lancing aid asclaimed in claim 1, wherein the blocking mechanism is activated when thelancet system is ejected from the housing.
 8. The lancing aid as claimedin claim 1, wherein the blocking mechanism is activated when the lancetsystem is inserted into the housing.
 9. The lancing aid as claimed inclaim 1, wherein the blocking mechanism is actuated during a lancingoperation.
 10. The lancing aid as claimed in claim 1, wherein theprotective portion of the needle body is transferred to the firstposition during the ejection of the lancet system.
 11. The lancing aidas claimed in claim 1, wherein the first position of the protectiveportion of the needle body is the same as the resting position.
 12. Alancet system for insertion into a lancing aid, the lancet systemcomprising: at least one needle with a tip for producing a skin opening;a needle body with a holding element that interacts with a holdingelement of the lancing aid when the lancet system is inserted into thelancing aid, wherein the needle body is connected with the needle insuch a manner that at least one protective portion of the needle bodyand the needle can be moved relative to one another; wherein theprotective portion of the needle body at least partially surrounds theneedle tip in a first position and in a second position, the protectiveportion of the needle body and the needle tip are spatially separatedfrom one another such that the needle tip is released by the protectiveportion of the needle body; blocking mechanism in the needle body,wherein the blocking mechanism is actuated by an interaction with alancing aid and changes the needle body such that, after ejection of thelancet system from the lancing aid, the holding element is preventedfrom interacting with the holding element of the lancing aid when it isreinserted again.
 13. The lancet system as claimed in claim 12, whereinthe blocking mechanism changes the shape of the needle body.
 14. Thelancet system as claimed in claim 12, wherein the protective portion ofthe needle body is a magazine housing that contains a plurality ofneedles.
 15. The lancet system as claimed in claim 12, wherein a part ofthe needle body comprises the blocking mechanism which is actuatedindependently of the protective portion of the needle body.
 16. Thelancet system as claimed in claim 12, wherein the blocking mechanismacts directly on the holding element and covers and destroys the holdingelement.
 17. The lancet system as claimed in claim 12, wherein the shapeof the needle body is itself designed as a holding element.
 18. Thelancet system as claimed in claim 12, wherein the blocking mechanism hasa preset breaking point that breaks the needle body when it is ejectedfrom the lancet system.
 19. The lancet system as claimed in claim 12,wherein the blocking mechanism enlarges at least one area of the needlebody.
 20. The lancet system as claimed in claim 12, wherein the blockingmechanism reduces the size of at least one area of the needle body.